# Technical Guide to Precision Sowing
Adjusting a planter transmission requires knowing exactly how many seeds must fall per linear metre of furrow. Machine manuals usually give approximate tables, but factors such as drive wheel slippage or seed size can alter reality. This tool gives you the perfect theoretical value: the target spacing between seeds.The Mathematical Formula
For agronomists and the curious, here is the basis of the calculation:
Spacing (cm) = 10,000,000 / (Population × Row Width)
- 10,000,000: Conversion factor from Ha to cm².
- Population: Seeds per hectare.
- Row Width: Distance between rows in cm.
# Why Use This Calculator?
If you measure in the field and your seeds are closer together or further apart than the target spacing, your machine is poorly calibrated. This tool also analyses the dosing frequency (Hz) of the seed disc at different working speeds, alerting you to the risk of singulation loss.# Keys to Quality Sowing
- Singulation: Avoid doubles and skips. 99% singulation keeps competition between plants balanced.
- Uniform Spacing: The coefficient of variation should be less than 0.3. Deviations greater than 5 cm reduce yield potential.
- Depth: Critical for uniform emergence. Adjust press wheel load according to soil moisture.
# Field Verification Methods
1/1000 Hectare Method: Measure a specific distance along a furrow representing 1/1000 of a hectare. Count the seeds and multiply by 1,000. For 70 cm rows the distance is 14.28 m; for 52.5 cm rows it is 19.05 m.Drive Wheel Method: Lift the machine, mark the drive wheel and turn it the equivalent of 1/100 of a hectare. Collect the seeds in a bucket and weigh or count them to verify calibration.# Reference Table by Crop
- Maize: 60,000 to 95,000 seeds/Ha. High response to density in modern hybrids.
- Soybean: 250,000 to 450,000 seeds/Ha. Great compensation capacity at low densities.
- Sunflower: 40,000 to 55,000 seeds/Ha. Very sensitive to density; excess reduces head diameter.
- Rapeseed: 300,000 to 600,000 seeds/Ha. Very small seed; requires excellent soil contact.